Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

Ragunda granite from the Mníšek glaciofluvial sand and gravel


Daniel Nývlt, Arnošt Dudek

Geoscience Research Reports 36, 2003 (GRR for 2002), pages 97–98
Map sheets: Liberec (03-14)

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Ragunda granite was found at the Mníšek near Liberec locality in the Mníšek glaciofluvial sand and gravel accumulation, representing the northernmost indicator found in the wider area of northern Bohemia so far. The clast was described macroscopically and in the thin-section as flesh red coarse-grained, altered and hematised biotite leucogranite with dark brown-grey quartz grains, flesh to pale red K-feldspars (microclines), lighter albitoligoclase, and biotite altered to dark green chlorite. The opaque minerals are hematite and magnetite; accessory minerals are sericite, epidote and apatite. The content of minerals in this clast is & K-feldspar 45 per cent, quartz 34,5 per cent, plagioclase 15,5 per cent, biotite + chlorite 2,5 per cent, and the accessories.